Long-term maintenance, '99 XK8

I’m about to take my 1999 XK8 down for some long-term stuff. The shop I’ve been taking it to (and which did the timing chain tensioners) says it’s time to replace the plastic thermostat housing. I love the car, and have decided to do this myself. I already have the SNG aluminum t’stat housing, and expect to also replace belts and hoses as needed. Right now, I’m only planning to do stuff accessible from the front, with the front up a bit on jackstands.

I don’t want to get carried away with shipwrights disease, but I’d welcome suggestions as to other items that I should be looking at.

Bob Frisby
Boise, Idaho
'99 XK8 and E-type S2 FHC

If you can turn a wrench your fine, If not let the mechanic do it.
The cheap plastic housing with crack and make a mess…
Depending on mileage now is the time for the replacement water pump along with new belts as well.
If your in the 75,000 mile club, just do the fuel filters and replace the pumps, its now or never but at 100,000 it will go.
Love that car, Enjoy that car, but take care of it or it will bite you.

I know most people ‘freak-out’ when I tell them that the way I replace the resin component with the aluminum is to remove all 10 of the intake manifold M8 bolts and lift the front of the manifold slightly to gain access to the 2 rear M6 bolts. (you only need an inch or so)

The way to help ensure that the intake manifold seals don’t get contaminated or displaced is to spray the intake with solvent and use copious amounts of compressed air to clean all debris from the area.

The throttle ‘elbow’ bolts can be left in place and used as a pivot.

I just pry the front of the plastic manifold up slightly and the thermostat housing bolts are easily accessed.

Once everything is tightened down I just press/tap the intake manifold back in place and then install/tighten the 10 bolts. (I use a dab of anti-seize)

I have NEVER had one come back for an intake leak or other P0171/P0174 issue.

Call me lucky (or daring) but I only charge 2 hours labor to replace the T-mostat housing and front outlet pipe because it is so easy this way.

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I agree with motorman. Lifting the intake manifold a bit is not a big deal. Just be careful with the fuel cross over between the left and right side fuel rails on the forward end. And while you are in there, replace the rubber coolant hose that runs under the intake manifold. It goes bad faster that the rest due to the heat. Play attention to everything plastic, especially in the coolant department. Way too many thin plastic coolant hoses. Besides the mentioned parts, the tiny reservoir coolant tank and the radiator end tanks are prone to age cracking. Especially on the right side radiator.

Thank you all for your thoughtful responses. Very helpful!! Should have mentioned that it has 74k miles. so I’m seriously thinking about the water pump. I take it that I want a metal impeller, which I assume the factory part has. But I’m really baffled by the disparity is pricing! The factory part seems to run about $500, The generic ones are a bit under $200, and there are some much cheaper than that. I hate to pay the big bucks without good reason! Any advice here? GTJOEY, you mention replacing “pumps”. Are there really more than one??

I’m not too worried about the wrenching. I’m pretty slow, and not much used to modern cars, but I’ll be OK I’ve got the manual on disk, and intend to take the time to do it right, but would like it running by March.

The SNG thermostat housing is an impressively good-looking part (especially for the money). It looks like a CAD drawing! I did spend a little time breaking sharp edges, etc., (obsessive, I know). but that’s not really needed. Gives me hope that it will fit perfectly!

Have a great Christmas!

Bob Frisby
Boise, Idaho

I meant all pumpms, Water pump and fuel pump…If you have an xkr it was two pumps for fuel…
100,000 miles is the week spot on those cars…transmission being the worst. Get it flushed and refilled even though they say its sealed for life.
Youll get a long time from that. If you neglect it, 100 grand and the car implodes.
Both v8 xj or xk…
Good luck.

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There also is that small electric circulation pump in the coolant system for cabin heat. When that stops working you won’t get any heat in the car. Unfortunately it’s located inside the transmission tunnel above the transmission. Save that replacement for ‘when’ you need a transmission rebuild (that’s ‘when’, not ‘if’).

That whole series of XK8 /xj8
We’re 100,000 mile specials
That’s what they were built for
I’ve had many but that’s their life cycle

Unfortunately you are exactly right. My first foray into the XK8 realm was with a 96 coupe that I bought in 2008 with exactly 100k on the clock. Felt like I was having a mid-life affair with an exotic women with a past. It was fun. Then one day I was pulling away from a light and it went ‘thump’. Limp mode. Transmission failure! The unavoidable A-drum failure at 108K miles. I had that fixed. Since then I’ve learned about all of her weaknesses. The compliant lower front suspension structure that eats the front tires. Too many plastic bits in the cooling system. This all on top of the well discussed weaknesses. But it looks so damn good! My latest fault was a breach of the trans fluid cooler inside the radiator end cap. It was an OEM replacement radiator. Yes I kept the correct mixture of water and antifreeze. But it corroded through and I had coolant mixing with trans fluid. Not a happy sight. This is why the LS drivetrain conversion market is doing so well! So many nice bodies available for conversions. Too expensive to fix. Just like 20-30 years ago with the XJ6/S.

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Gtjoey hit the nail on the head!

I recall reeeeally Jonesing for an XK8: then, in 2003, I began reading all about the joys of XK8 ownership.

I chose the hot rod!

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Its like any relationship lol. Take the good with the bad. It is amazing how some little things just pop up all of a sudden like with them. My father in law picks on me sometimes saying stuff like “I thought jags were supposed to be really advanced and good! The problems you have make me think they’re crap!” :cry::cry::cry::cry::cry: